This project involves the mapping of ultrasonic fields for the purpose of calibration of medical ultrasonic transducers. Two techniques are being pursued. The first uses data acquired from passing light through the sound field and considerable data reduction to obtain a point-to-point calibration. As the light is non-intrusive, this technique can yield an absolute evaluation of an undisturbed sound field. The second technique uses liquid crystal interfaces to map the sound field. It is visualized that the device based on liquid crystals could provide secondary standards.